Rotary fan.



0. STOTT.

' ROTARY FAN.

APPLICATION FILED IAN. 22. I9II.

1,261,457. muted Apr. 2,1918.

/b l Z Zd/iz-egsq; e5 i SHP/Loi?" m align/g OSWALD STOTT, BIRMINGHAM, ENGLAND.

ROTARY FAN.

spcmeation of Letters Patent.

i Patentednpl-.a 1918.

Application 'illedJanuary 22, 1917. Serial No. 143,764.

To all whom z't may concern.'

.Be it known that I, OSWALD STo'rr, a subject of the King of 'Great Britain, residing at Ruskin Chambers, Corporation ystreet, Birmingham, England, have invented certain new and useful Improvements in or Rel lating to Rotary Fans, of which the follow:

in isa specification.

y invention consists of the improvements hereinafter described in or relating to rotary fans, the said improvements havlng for their principal object to obtain increased eiiciencyin the said fans. l

In order that my invention ma be the better .understood I remark that it 1s known to those conversant with rotary fans that with fans of the type technically known as Screw propeller fans, with a constant rate of rotation, the 'driving power for the-fan must be increased as the outlet or discharge open-l ing is diminished and with fans ofthe type known as centrifugal fans the driving power required is decreased'under the samelcondit1ons.

My invention consists in combining fans of the two types referred to so as to obtain a composite runner in whichV the air from the one fan does not pass through or enter the blades of the other fan and wherebythe following advantages among others are obftai'ned as a result ofthe opposing characteristics hereinbeforel referre to of the' said 'lhe ower required for running the com o slte an is -more-nearlyv'preserved constant or var ing degrees lof opening of'outlet y' 'than with either type of-'fan usedv separatelyg. Further, by k.combining the 'two' orlpropeller fan only were used,

w111-further describe my invention' iin connection with the accompanying drawing;

Figure 1 represents in front elevation, 'and Fig. 2 in vertical section a composite fan or runner constructed according to my invention'. v l

' Fig. 3 represents in section the said composite runner in a casing provided with A'diffuser vanes. n

Fig. 4 represents. diagrannnatlcally'. the

relative direction of the blades of the screw rger volume of air 'may be dirs'- or propeller part of the composite runner and the difuservanes of the fan casing.

Fig. 5 represents in diagrammaticsectionmy new o'r improved composite fan or runner arranged ma slngle inlet volute casing.

'Ihe .same letters of reference indicate the same-,parts in the several figures. of the drawing.

ais thel runner shaft and b the hub or boss of the runner which is keyed to `the said shaftthe said'boss b havin the coneshaped disk cto w ich the inner ends of the bladesd'of the centrifugal ian'I part of the runnery are fixed, the outer ends of thesaid blades being attached to a rin e having on its outer side or periphery t e screw or propeller blades/. The rin e is connected to the boss b by stay ro s or spokes g in any convenient way.

The direction of the blades d of the centrifugal part of the "composite runneris parallel with the axis of the runner as is fixed thereto l usual in 'a centrifugal fan,'but the blades v may be radial, or inclined o r curved or may be artly curved and ypartly at. l

he air which isdischarged from the tips of the blades of the centrifugal portion of thecomposite runner is guided by;the conca ve surfaceor inner side of the ring e and made to vtake a direction similar to that of the air dischargedY from' the inner edges lof the screw or propeller-blades f of the comfv posite runner.

To obtain the highest efficiencies 'from the new or improved composite runner described it is arranged in, a casin h (see Fig. 3)"

vhaving within its tinner en or part diffuser blades l n It may be found necessary or deslrable to give tothe par'ts of the diffuser vanes which receivethe air yfromv the srewor propeller blades a. different inclination or shape fro the', arts of the said vanes which receive t e air rom the centrifugal `fan blades.

fThe vanes.. will preferably' Jbe provided y with an annular partition or ring m between the casing l1. and the 'inner drum to which the inner ends of, the vanes are fixed.

If desiredl the composite runner may be arranged in a. single inlet volute casing as is illustrated diagrammatically in Fig. 5, or une of the said runners may be arranged in y each of the two inlet openings 'of a double inlet volute casing.

I wish it to be understood that two or more of my new or `improved composite runners may be yused in series, or the said fan blades, the centrifugal blades being ar ranged within and separated from the said propeller blades that the air from the one does not pass through or enter the blades of the other.

2. A composite fan comprising a shaft, a

i conical disk mounted on the shaft and having a series 0f centrifugal fan blades projecting outwardly therefrom, and a ring surrounding and secured to the ends of said blades and having outwardly projecting propeller blades. A

3. A composite fan comprising a shaft having a boss thereon, a conical disk secured to the boss and having centrifugal blades projecting outwardly therefrom, a ring surrounding and secured to the ends of said blades and having outwardly prooutwardly' therefrom, a ring surrounding and secured to the ends of said blades and having outwardly projecting propeller blades, and a casing surrounding said fan and .propeller blades and having diffuser blades therein.

5. A, composite fan comprising a shaft, a

conical disk mounted on the shaft and havi ing a series of centrifugal blades projecting outwardly therefrom, ya ring surrounding and secured to the ends of said blades and having outwardly projecting .propeller blades, a casing surrounding said centrifugal and propeller blades, a drum within they f casing having diffuser vanes, and an annular partition between the drum and casing.

ln testimony whereof I have hereunto set my hand.

oswann sro'rr'. 

